Hi, how can I connect the plc output to the arduino via optocoupler? Do you have some schematics? Thanks
Have you had a search of google? This has been covered over and over and over again.
In your previous post you mentioned speaking with a professor, so I take it this is school work. So maybe you should at least make an attempt at learning on your own. Come back when you have problems or something you don't understand. But we would be ripping you off on your education if we just gave you an answer.
I thought you said the PLC had relay contact outputs.
Post a circuit diagram of the PLC output.
No proper answers without that.